SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '856184eefd9cf8dec4ad5550617b5e65d3942fdfb671ca17042ddf72e3ec20d0' 
  AND token = 'OdmqzMNJnW/vjNnJtrnm2BfhPgtXbGtaeTXtfXlmF7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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