SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26581bcd848a65963eea54bf724153e8c6cf7c79592717369e07345b09bb487c' 
  AND token = 'QoMz8XPU+whexO4hazYTNKEdxxrI2Cl+T/uK9VR7FQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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