SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '248a821443343309989aaf42d5a4d19b0315a9e76678bf5e5c64083610cb4fa1' 
  AND token = 'kcw2vpxqHiHI3PX4J/7qG/ileqRQfvfp6JYSWXBEnds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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