SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c428eb7354d92cfafc782fa420f130060469420a5b4c905d7442cb4872c861a9' 
  AND token = 'Y//QGBQXgFTkP4Sxp3BNwKh7afmkYJyK1GS6GsXTkJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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