SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c8fc9698891a6b70f39ddcdfc2c975decde57abb215080300e3d7f9724559ca9' 
  AND token = 'Scr9DVbeKTE4HEvVH0ioyHgC2G3ZFAuYzpRU6HVDzlE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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