SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f29653e1b7d494e4538149528405ebf0929a268898b5183f5db2cdda867e45cb' 
  AND token = 'xBLpmmr/KtaW4AgU1mbOE4o6quHWiTFrvuUUQdTAECk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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