SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a1e09b5dd3a8013aae3104ff81f98a06c0baa85e9d9b6567b1fbedac5b7e9dd' 
  AND token = 'xPmb8TLzrp46mdCt2kV1rric8fF7GsHqx16cYkRaUc8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00202

JSON explain

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