SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6862bb6b7fdc2480bff6cd969f178b39c2a483a7a8500f7f985b4198e4e749f3' 
  AND token = 'kcgKWb3nmUbDWt10Mw+q4YbxcL/EnAmGT++1hqtBtFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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