SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd499581566dd042d109b56e4fc0e151be272183fa6c735cce67fdffa30c7c5e' 
  AND token = 'yzoEB+HYvcG1HpQB6jbzQqKMiZUbeKiOkHvH58pQQPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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