SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9789bc2b3188210359104533403aa7e3fba2b20b56d37a1d23460f91c90df093' 
  AND token = 'nsXeo/DHxQKdRExqRtuvPHI1s5q97IW4uLiKylCgWUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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