SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0ad518488d0d61d62e28680fc63affe184fdfabbff4c02f282137df3d378099' 
  AND token = 'p+BZ4gNFfo8i1yFHj9LoYdlrSvorgg++1QnZQIPdDbA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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