SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb7605bb3f962e383844d532ec724b19985b148eed45ac3434a878ebf198882d' 
  AND token = 'KjyNwhebdR+urxGW+J+fm3j/fHxBZcP7CzW301X+meY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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