SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e35892b6c5788bd417d671a8d69a396c2b53818541f4f3769c5606172bc01c1' 
  AND token = 'NBHw9RoifGBRXRajHggnBpoGgGmgDLguXtMLF5xgwLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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