SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1dc9878de2e246c1cfdd780a6ca12f717f649ee4291d19783763f02623ee5682' 
  AND token = 'uTMZRmJoUGWSBHpDR/tl6neEQKP8cSgdW4fI8XGRJe8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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