SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c98e0327abebc25f557119cb45ec5e9e3cbd114b894fa589f2055e869d2c9690' 
  AND token = 'zvmG0khYvjFKLrO6WHkYsNltCr1m346b9nw4PJXZ2us=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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