SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf24d425c9b1b8f2d4637d6235fb4fc32bb5a680400bf2cafa27625430df5959' 
  AND token = 'n5zOXmDLF2OQ7hHFivW7YSBM42pbWCNCHTyGH4saBsk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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