SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14dd9e3360cfa013dc95087ef85ffd10e36bfe5de0384b0605da6e2f763be7c7' 
  AND token = 'ZxaJu8R63BUFQ7l3SG9mgbYh7oz+VGX+xwyF2/4IvCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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