SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59a26510526cc98cf5abff4ef25d09738005874738a94e6f703dee4582e7e38a' 
  AND token = 'qzAW6cDz+y3ZS23luixtQTiAQMWpsruxiQ1tsiP5Kko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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