SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '498bdcae72a65251f865c2f9b1667034ca09300ef8943f1710324cbded0701c2' 
  AND token = 'hcFUSz7dOQyLNWsJaQz622epZIsTGnGbrdtVdjrx+Zs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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