SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b3d93010d8811695bea4e8ce8b34e2c1d1f7c5c3f7fd17a76621f6d2d75813d' 
  AND token = 'BJjwyC/T44Z1DpN5gACv9M8LTCjsdbgRP5GEalQ6FBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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