SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83ac7b16f63550fc9fa4476c069c672c3b3b4d543407667cb552d4822ca5d1b5' 
  AND token = 'JLJPq64PB8x/ZXCP+lTAAsqMRDeghujkHsB0AFc4wjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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