SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '700897c6c4c639047e76a5550df8da55b16904e5d82319335e6c70a30bcce525' 
  AND token = 'UGs6Sf+++WiCVhF0a7ZlGCcaMYOvXsXqBWBR8/ntPQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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