SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3970aafc43a8e4e1767058ac7a95c2eb1bdc612f3865128f6706d88250f0fcb' 
  AND token = 'FOtjQrEM4KzPu2fNhwOMTMxQxp7DT+l3QoO1h8meGdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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