SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd3dd52874d8bdee5fd2a5a7a3db3f5645a72af9e3221157abe15604bf92b364' 
  AND token = 's1U/eLXMJVkU0x+yyKwKwVGztgpT4Zp8NTPUb9Xhgdg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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