SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4462ccd3673dc788127c5e324555cba878d5dbf1fca8708d242181cf3621313' 
  AND token = 'rtbGZj1661eVxm1rlYsFEWx4jPxXftJqdEfSH78l+yQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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