SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b0d5e535ebcdee3032634b9444b54f1589ec15fac0a58b610d062546fa551e6' 
  AND token = 'BShZwiqdDJK7isyKY9yGU6F/lvNwRYfqw4LqXLCkS3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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