SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f068bd8c2be4d7c837884d93d0db688b9da5d64036d245b55ef118735b492296' 
  AND token = 'LshtjjmPiaWjmR0KSJVN58gpY+/2r4DA6C1haaOGmXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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