SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6b5fcbd3e6f4ac10d59875ceb07ffdbf17c69fdcc2c96799a8fdee0405d8c8b' 
  AND token = 'glWRvxJ2BbNjd0j7qkLx9MwrItfZCqAyBPqNEo3FCYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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