SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8042e23bae676ec5ea0064a7f771f08136783d33b8c41cd9f29c7f5135b2a6a0' 
  AND token = 'sl9iDLUzRxqgiGEeVrKguVWKGobjwVr3svJzW5LD8l4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00068

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}