SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd017861b1d5cfa1f20e8c424bea2e8d779af78401552e40b89cdd3c439303f19' 
  AND token = 'xmPRBE/nzsPWzdnJZgv8UY1q96bjxaQPtYEqpnGQRSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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