SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '470ca04cb7ebce2b496ce6149e5af989931cc8eb9dde1e70f6f4720891c0db0c' 
  AND token = 'kPDrLpNDffl1i3I0svHqg/WWlRCDbubSwwluwfKxkBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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