SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a731df5f3ad01100f51b46e699bf1cb8ca1de0e48f534bf6a4b9b0735f6de2a5' 
  AND token = 'wwivxchA+/4D0nFWGmspVg44Ew4ovKYLWonEJh+95qY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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