SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfe684e1f4481359caa404fba75a6751dfae27afa864e21b1263307c72b739b2' 
  AND token = 'R5c4t8b1A2rL9Ps70a+L/xwPlDi8jhnLicFckzyatn8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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