SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c71ad8b3fd242b531845b554c0735d65ee087b32944021469879783ab059769' 
  AND token = 'YgyvrXpCqV8onotdhY5ZBvrUrdnaWaW9Sluo2uuN3YU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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