SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '711ccfc38efdbb9f5f4e49ec682af93bd716553582f5f45ddc1af952096ad461' 
  AND token = 'FFZVizA5mJIDjfZQz9kRAys/IVXwW9hr/2JhQB78l6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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