SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6129ac138b96a377bb87ffb06c324f3d82c2c17ae44aa33a22b47161933b2af7' 
  AND token = 'QIAtVrakYpzv6SMMgoP8ssKdeLPxj6tceVnBXdjq+EM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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