SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b17dcd2691797438e6228a29949a3c0a7af2c53c41928499cdc7d8e9a4fbd465' 
  AND token = 'VDkIsjx1vdprIQNHN0X624dIB5w2HPYTWBqXu+szgtw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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