SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '05b87ee1c75a8b96ff3792b16d0b4a84013b72c1f4b59b9c6ca725a9725044f2' 
  AND token = 'KljYPopQQmFMHw+8nat9cm5zKZ4YdTUCzXpCZCygZdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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