SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5343275353c4be120aea90196b480d3de723001b5b1ef596bfc45fb6a09399fb' 
  AND token = 'tLy1NG9B9CUlpdbExtf6i1fIKfWWZbEjjtViJXuSBLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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