SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b03c66deac80448af8d584424f3e71df12ceb30043ae55f0e0e29dcdfc49f659' 
  AND token = 'nBQfpmnrjg7EFrKogkklzLeDNocSv5XrNgx+ABDPRwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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