SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67c8a9445d1a23520aa21c8ac52cd49b1a05d25f84bda1a3658a42073f937923' 
  AND token = 'NPQ9I4F12Ypn/pkllFarIy0Tt7qpBRHremOvQJngFQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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