SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97b301d16b1109cea752e49c14e9821d6ca3bddc949f8e91326e63aba9f25df4' 
  AND token = 'TeBnhyMrBzwBenwk5mD8V09IoLpJD7eiWeiyPESa7j4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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