SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7739a8b10719e17362e9f4139c5968ee9ffeec41a60738b4ab8505807b6a7692' 
  AND token = '/9FEEWjS6vFKwEUPaZgp7wQmJeMwAyhosfzZql7WNrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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