SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adcadd0a7ece0b36ae84c6e70d291bd56f749751dd172ca6fdbbe40955e00dce' 
  AND token = 'MUaP5RleiCnn8jxDHXWwr7mkZ0inW5hO+I2VAZrqU0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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