SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b73a6cbea4a6cce1d2838a0eb82108c7886f0ddc72ca5991909911460322655' 
  AND token = '6+L28ZnuedHNpSz7Bg0AB05Ct0Af4dXqpk3wkDRNK6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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