SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e1b329613d72e1212e9b27419ae857f6f8ae665db8cebecb1746d796a57d98e' 
  AND token = 'fQYYjePQGhy/bvZhi6SCTPdYWpotPVWGZCUHxJml0Pk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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