SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '709325031ba216bd84c1fae23dc69df97a00fdc345ab3fd01745da1c3f6b6c09' 
  AND token = 'c6wJvttANBvvhSwX7Iei2YYCWPD8q8BaB3hij6/Gs+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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