SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31805dfd765b70ceedc919c9ec547c3517d49b5224688d8de9957968e7854b8a' 
  AND token = 'jRRJsMjHaW18u77B7MJZV63zczc+Lapi27R8lZntuQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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