SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adef8331a6166b0b4ad1defe8b4a3aba1f4d55ff9350118b7ff81b2f8ce1fcf2' 
  AND token = 'YRFhNQuxBFo4/yiwYAy3kxUkK/lpeKrGpMuetczy4wQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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