SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0fe02782aa3b8c318533828e426baa1b0c1c3b5269141dad9ff2b40cb3780da' 
  AND token = 'iOAnxa4wnvwU9rdoelEx48GS7AIrvSoENTxNUwXWalo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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