SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7baf96fef483405aee12ac90091e467cf22da6a3c0a22792391989bdff27523' 
  AND token = 'GquHWIEq/RJgUSiIGZkqv0RCvOBpWY5xsoySv/kQcIg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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