SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe57c1784380b5d2fcca801753081a07bf0b5bbe1f571647fa04540cf83d034d' 
  AND token = '0JTjXUyOxKhN6HKi9IY/CW60iLfpp2myVy9RFxrek7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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