SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c8c41cbeabfc700530cc072a96ea3f2290a98fe4d8858c030973ac266be370b' 
  AND token = 'OTWFhaO90hbJ2pddxROi7NdYsFNasz79IeHwvfl+Rsc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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