SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9ec980758e6347ea357c158775e9a10eb32a49396f4a57158f5843f26c604f6' 
  AND token = 'dYprSo/2C5KYnKuYuWZjVwi8N+W1CHK0iBzZWsoPBV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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