SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6ca0822f3d133c90294e52206f4551e8ecda8342ef7d3be595cbf9a1d4e0c57d' 
  AND token = 'lCYx8+YWJ04gUJ44pQfKhUzgfC2hq91vVFNcWIZjycQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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