SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '364c3619ab65cf5a8367db3d11c06f75ee1daaac33e439fd70d4f43538d34cd9' 
  AND token = 'b2cC0ALCLOkEusosKAjJp5rXE2rGjMCHpiEaDXhy7TQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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