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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2ad9887e6cf11ff84a53fdb3af116d7808b5cbc9f0c7a65af19c973bbc27ffa' 
  AND token = 'NGsqCpqip7mE9hf+JE2rwax19CqWGAS5vFwFx9TW8lM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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