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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3f4548e904670c57263b3c10d68bf337c5a8266cc9603c9544d9ad96c6e492d' 
  AND token = 'rx/xZUx4ttiDDsw5nSs8IUHFPyaEO9Z4RBcI1xDS1IE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}