SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '379b67c9bcd8144b4d83cfacd03e10a5e18dd9a65849618e8c4fc383490f56f4' 
  AND token = 'LmlGeLuaftB993W/RQmYMy3gTzhwqU9zhZtcHYdmY2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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