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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b88875e55b33e0188dd3efe5e63aa2aa7c0ed1ee3a33aa34f596378d46139008' 
  AND token = 'pwpgsiMFKyRDE1zDOczJuKGm9G1L7jvJ7CxzmxWjHKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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