SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2a3385b302587856cb420b43d343476873c678f819fd39bd4a587dc56fe6024' 
  AND token = 'ynJnfP7hp36jsCM5xI0ySVwFXMVenWR2yoZlanF53Go=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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