SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c804f90f29049565665734f17ea47c2e02e17c3f666fa3d0ec80fc612bae831' 
  AND token = 'lqNnx1ZJjXNqyzFfvDEQI2nM17CUNK3DyQBXgaDuUUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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