SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebcecf3dd5d01c4ee38652ae4628f3db8fe6fe3c3225057c46a0e41399f4512e' 
  AND token = 'KXqfcfdK/hRRgmxw5wxLfCPO6mzPnLZHsXfufPWltRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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