SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe2e985c335aa580ee4a3ddca718ea74c06031e9d6eebe8edabed8ab18e99b0a' 
  AND token = 'kZG9EtVFWN7rTGT1WSzTlkCTigmvjAranf/Ov+5lPG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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