SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6e163d639c6110b493d2743aea555845c44aff065977d221872ccfba2b8421c' 
  AND token = 'IPhl0WwzmLzZSQWZjw0JaH0GXiuYEVEEw+N7OO65tkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}